In recent years, thin and light weight laptop computers have increasingly been developed. Along with such development, a decrease in thickness as well as enhancement in quality of the protective film of polarizing plates, which are employed in the display apparatuses such as a liquid crystal display apparatus, has increasingly been demanded. Further, liquid crystal image display apparatuses (also called liquid crystal displays) of computers as well as word processors have increasingly been employed in which a reflection minimizing layer is provided to enhance visibility, undesired image capturing is minimized, and in order to achieve display performance of minimizing glitter, an anti-glare layer is provided in which the layer surface is roughened.
Various types of anti-reflection layers as well as anti-glare layers have been developed depending on their need, and their performance has been improved. In order to enhance visibility, methods are employed in which reflection minimizing function or anti-glare function is achieved by attaching various front plates exhibiting improved performance to a polarizer and the like in a liquid crystal display.
The aforesaid anti-glare layer functions as follows. By blurring an image contour reflected on the surface, the visibility of reflected images is degraded. By such action, during the use of an image display apparatus such as a liquid crystal display, an organic EL display, or a plasma display, reflection image capturing becomes almost unnoticeable.
The aforementioned properties can be provided by an adequate microscopically roughened structure arranged on the ultimate surface of the front panel of an image display apparatus. This method includes the technique of using particles (refer to Japanese Patent O.P.I. Publication No. 59-58036) and a technique of applying an embossing process to the surface (refer to Japanese Patent O.P.I Publication No. 6-234175). Further, Japanese Patent O.P.I Publication No. 2004-4777 describes the method of forming an anti-glare layer by coating film wherein particles are uniformly dispersed. A great number of coating and printing techniques are mentioned as the coating methods for forming a coating film. Flexographic printing technique is cited as one of such methods. However, in this document, the microscopically roughened structure is formed by particles, and the binder (ink) itself is uniformly coated. The document does not mention the arrangement of a microscopically roughened structure according to the presence or absence of ink itself.
However, according to the method of using the particles, the microscopically roughened structure is formed merely by allowing particles to be contained in the binder layer. This requires the particles to be adequately dispersed. This makes it difficult to achieve effective and stable formation of a desired microscopically roughened structure. This has been a great stumbling block in ensuring sufficient glitter preventing effect as an anti-glare film. In the method of forming a microscopic structure using particles, the aforementioned problems have remained undissolved, independently of the coating method. Further, the method of forming a microscopically roughened structure by embossing process and others has been unproductive. Especially stable formation of a microscopically roughened structure has been accompanied by great difficulties. Sufficient results have not been achieved in the reduction of glitter and anti-glare effect.
In recent years, the image display apparatus is required to provide greater visibility due to the need for displaying color images with higher definition. For example, the aforementioned conventional anti-glare film is insufficient to meet the requirements of the ultimate surface of the liquid crystal display. The clear hard coat anti-reflection film has not yet solved the problem of undesired image capturing of the fluorescent lamp. A great number of technical proposals have been made on the anti-glaring anti-reflection film wherein the anti-reflection layer (low-refractive index layer) due to optical interference is coated on the anti-glare film (refer to Japanese Patent O.P.I Publication No. 2001-281410, Japanese Patent O.P.I Publication No. 2004-4404, Japanese Patent O.P.I Publication No. 2004-125985, Japanese Patent O.P.I Publication No. 2004-24967, Japanese Patent O.P.I. Publication No. 2004-4777, and Japanese Patent O.P.I Publication No. 2003-121620). However, these techniques have so far failed to provide anti-glare and anti-reflection properties sufficient to produce a display apparatus for ensuring excellent visibility.